Caster devices are generally secured to the bottom of tubular legs either by one-piece or multiple-piece caster sockets or by multiple-piece expansion devices. For example, in U.S. Pat. No. 4,805,260, a slotted sleeve is disposed within the bottom of a tubular leg. A caster-stem or bolt, extending upwardly from a caster, extends through the sleeve and is threaded into a conical expander, the expander extending down through a central passage in the sleeve. As the bolt is rotated, the conical expander is drawn toward the caster, thereby expanding the sleeve against the interior walls of the leg and tightly securing the caster and expander device to the leg. A similar device is shown in U.S. Pat. No. 2,173,950.
Typical of the one-piece caster sockets are the devices shown in U.S. Pats. Nos. 2,294,807, 2,169,882, and 1,649,526. In these patents, the caster socket is generally tubular with an outwardly extended flange at its base and is split upwardly from its bottom to a point relatively close to a domed upper end, thereby forming two, somewhat resilient and inwardly deformable sections. The socket may then be inserted into a hole defined in the furniture, the lower sections of the socket deforming slightly inwardly, thereby providing a friction fit to hold the socket in place within the hole. In U.S. Pat. No. 3,128,495, a caster socket has a body having no slits and having, at its top and bottom, a series of incompressible, radially outwardly extending splines. The upper and lower portions of the socket are thin walled, allowing them to deform slightly inwardly upon insertion into a tubular member to provide an internal friction grip.
While the multiple piece expansion devices provide a means for securing a caster to a tubular member, they can be expensive and somewhat time consuming to assemble and install. The one-piece caster sockets, on the other hand, may be less expensive and easier to install, but they may not be as reliable or long lasting.
What is needed is an inexpensive, easy to use and long-lasting device for securing casters to furniture and the like.